Humidifier

ABSTRACT

A boiler formed by a water containing vertically disposed casing having a heater in its depending end portion is provided with a steam outlet at its upper end portion. An overflow tube, connected with the depending end portion of the case, drains minerals and salts tending to accumulate in the bottom of the casing. A thermal switch secured to the depending end of the case operates a water flow controlling solenoid valve which refills the casing in response to temperature changes of the casing in converting water contained thereby to steam.

United States Patent Dines HUMIDIFIER [72] Inventor: David R. Dlnes,4801 N. W. 34, Oklahoma City, Okla. 73122 22 Filed: April 15, 1971 21Appl.No.: 134,249

[52] U.S.CI ..219/27l, 126/113, 261/142 [51] Int. Cl ..F22b 1/28 [58]Field of Search ..2l9/271-276, 284,

[56] References Cited UNITED STATES PATENTS 1,580,293 4/1926 Fitzer..2l9/273 June 13, 1972 3,219,796 11/1965 Grafet a1 ..2l9/285 PrimaryExaminer-C. L. Albritton Attorney-Robert K. Rhea [5 7] ABSTRACT Aboilerformed by a water containing vertically disposed casing having a heaterin its depending end portion is provided with a steam outlet at itsupper end portion. An overflow tube, connected with the depending endportion of the case, drains minerals and salts tending to accumulate inthe bottom of the casing. A thermal switch secured to the depending endof the case operates a water flow controlling solenoid valve whichrefills the casing in response to temperature changes of the casing inconverting water contained thereby to steam.

5 Claims, 4 Drawing Figures PATENTEDJUH 13 m2 FIG.I

I lll I DI NES /NVENTOR.

DAVI D HUMIDIFIER 1. Field of the Invention The present inventionrelates to humidifiers and more particularly to an improved humidifierwhich may be used as an individual unit or in combination with a forceddraft heating unit.

It is generally well understood that for comfort it is necessary tomaintain an adequate level of humidity within the air within buildingsbeing heated. Further, it is recognized that a proper level of humiditypermits room temperature to be kept slightly lower with no uncomfortableaffects, thus, lowering fuel costs and further preventing furniture andother household items from drying out.

2. Description of the Prior Art A plurality of humidifiers are disclosedby prior patents which generally are used in combination with a forceddraft furnace controlled by a humidistat, such as US. Pat. Nos.2,347,490; 3,294,081; 3,305,173 and 3,443,559.

Some of these prior art humidifiers employ the heated air from thefurnace for evaporating water contained by porous elements in the pathof hot air flow while others utilize a fine spray or mist or water inthe air stream. This type of humidifier is generally bulky and usuallygets out of order, such as by minerals and salts, deposited by thewater,'clogging the orifices forming the water spray in the air supplyand collecting on the air ducts interior wall surfaces. Humidifierswhich employ a separate heating element for evaporating water frequentlybecome inoperative as a result of minerals and salts from the waterforming a scale which restricts the water and steam openings.

This invention is distinctive over the above named patents by providinga humidifier which may be operated as an individual unit or incombination with forced draft furnaces. This device includes means forremoving scale formed by minerals and salts in the water when the latterbegins to accu mulate. Further, this invention is distinctive over thehumidifiers disclosed by the prior art by its simplicity andconstruction of relatively few components, thus reducing its initialcost, which includes a temperature responsive switch actuated by a waterevaporating boiler and requiring only a source of water and a source ofelectrical energy to place it in operation.

SUMMARY OF THE INVENTION A boiler is formed by an elongated verticallydisposed casing having a heating element containing tube member sealedwith and extending upwardly in the depending end portion of the casing.The upper end of the casing is provided with a normally open steam vent.Adjacent its upper end portion the casing is connected with a watersupply pipe having a solenoid controlled valve interposed in the watersupply pipe. An overflow tube is connected with the depending end wallportion of the casing for flushing the casing into a drain each time thecasing is refilled. A temperature responsive switch, connected with thecasing wall at its depending end portion, opens the solenoid controlledvalve for' admitting water to the casing in response to a temperaturerise, above a predetermined setting, each time the heating unitevaporates the water, contained by the casing. Water entering the casingreduces the casing temperature below the predetermined setting of thetemperature responsive switch thus closing the solenoid operated valve.

The principal objects of the invention are to provide a humidifier whichutilizes a boiler to vaporize water which is automatically refilled by atemperature responsive switch each time the water in the boiler isevaporated and which flushes the boiler free of scale accumulated in theboiler each time it is refilled.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 2 is a horizontal cross-sectionalview, to a larger scale,

,taken substantially along the line 2-2 of FIG. 1; and,

.provided with a float-type ball valve and cage means FIGS. 3 and 4 arewiring diagrams illustrating different embodiments of the device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Like characters of referencedesignate like parts in those figures of the drawings in which theyoccur.

In the drawings:

The reference numeral 10 indicates the device, as a whole, comprising aboiler 12 connected with a water supply pipe 14, overflow tube means 16and a controlling thermal switch 18. The boiler 12 comprises anelongated vertically disposed casing 20, preferably formed from aselected length and diameter of copper tubing, having an elongateddownwardly open tu bular member or heater housing 22, of similarmaterial and diametrically slightly smaller than the inside diameter ofthe casing, vertically disposed in the depending end portion thereof.The depending ends of the casing 20 and housing 22 terminate in a commonhorizontal plane and are joined in fluid tight sealing relation by acentrally bored seal 24 having an annular flange 26 interposed betweenthe innerwall surface of the casing and the outer wall surface of thetubular housing 22 thus maintaining the housing coaxial with respect tothe longitudinal axis of the casing 20. The housing 22 coaxiallyreceives, in close spaced relation, an elongated electrical resistanceheating element 28 which is maintained within the housing 22 by acentrally bored plug member 30 extending through the bore of the seal 24and frictionally received by the depending inner wall surface of thehousing 22.

The upper end portion of the casing is provided with a diametricallyreduced tubular vent 32 for exhausting steam to the ambient air in themanner hereinafter explained. A cage 34, having a seat 36 opened andclosed by a float-type ball valve 38, is coaxially disposed within thecasing and connected to the upper end wall 40 of the casing incommunication with the bore of the casing vent 32. v

The drain tube means 16 comprises a first tube 42 diametrically smallerthan the casing 20, which is coaxially connected horizontally, at oneend, with the casing wall in close spaced relation with respect to theupper limit of the sealing flange 26. Intermediate its ends and adjacentthe casing the tube 42 is deformed to describe a substantially U-shape,indicated at 44, defining vertical parallel leg portions 46 and 48 withthe leg portion 48 projecting upwardly substantially coextensive withthe upper limit of the casing 20. A second drain tube 50 is horizontallyconnected, at one end, with the first tube leg 48 at a selected positionintermediate its ends, preferably spaced above the upper limit of theheater housing 22, with the other end portionof the second tube 50turned downwardly and opening into a drain, or the like, indicated at52, disposed below the lower limit of the first drain tube U-shapedportion 44. The upper end portion of the first tube leg 48 is similarly54 which is normally open for admitting air to the tubes 42 and 50 toprevent a syphoning action and draining water contained by the casing20.

The water supply pipe 14 is connected with the wall of the casing 20adjacent its upper end portion in upwardly spaced relation with respectto the horizontal plane defined by the connection of the second tube 50with the first tube leg 48. An open-closedwater control valve 56 isinterposed in the water supply line 14 and a solenoid controlled valve58, including a solenoid coil 59, is interposed in the water line 14between the valve 56 and casing 20.

The thermal switch 18 is a conventional temperature responsive switchoperated by differential expansion of a surrounding metallic caseoperating a low expansion metal bridge, contained by the case, whichopens and closes a pair of contacts in the case manually adjusted by theexternal end of an adjusting screw 60. The contacts of the thermalswitch 18 open on temperature rise. This thermal switch 18 iscommercially available from Fenwal, Inc. of Ashland, Mass. and ismarketed under the trade name TI-IERMOSWITCl-I, series No. 30000,relating to nonindicating surface mounting temduction means comprising aslug 62, generally rectangular in transverse section, formed of heatconducting metallic material, such as copper, having a predeterminedthickness, is interposed between'the mounting surface of the thermalswitch 18 and the outer surface of the casing wall for increasing thethermal inertia of the switch 18 by forming a time delay in theconduction of heat transmitted to the thermal switch 18 from the boiler12. g

A spacer 27, which may be an extension of the flange 26, is disposedbetween the walls of the housing 22 and casing 16 substantiallycoextensive with the thermal switch case for more efficient heatconduction.

Referring more particularly to FIG. 3, a source of electrical energy AC.has one source wire 64 connected with the heater 28 with the other wire66 of the heater connected to one terminal 68 of the thermal switch. Theother current source wire 70 is connected to the other terminal 72 ofthe thermal switch through an oiT-on switch 71. The contacts 68 and 72of the thermal switch 18 are bridged by an arm 73 in FIGS. 3 and 4 forillustrative purposes since in actual practice they make and break witheach other. Other wires 74 and 76, connected, respectively, with thethermal switch terminal 72 and wire 66 are connected at theirrespective'other ends to the terminals of the solenoid coil 59.

' OPERATION In operation the device is assembled and connected with thewater supply pipe 14 and current source A.C. as described hereinabove'.The device is placed in operation by manually opening the water controlvalve 56 and closing the off-on current supply switch 71. This placesthe resistant heater 28 in operation without water being present in thecasing 20. As soon as a predetermined temperature is reached, determinedby the setting of the thermal switch 18, the thermal switch opens itsnormally closed contacts, by moving the arm 73, so

that current is applied to the solenoid 59 over the wires 74 and 76 thusopening the solenoid valve 58 and admitting water, in-

dicated by the lines 78, to the casing. The water fills the casing tothe level of the connection of the second tube 50 with the first tubeleg 48 wherein any excess water entering the casing 20 drains throughthe second tube 50. Water entering the casing 20 reduces the temperatureof the casing and this reduction of temperature is sensed by the thermalswitch 18 through the slug 62 which closes the thermal switch arm 73with the contact 68 defenergizing the solenoid coil 59 and interruptingthe water supply to the casing 20 wherein the resistance heater 28heatsv the water 78 and vaporizes it. Steam, not shown, is generated andexhausted through the casing vent 32. In the event of malfunction of thethermal switch 18 causing the solenoid valve 58 to remain open waterentering the casing is continuously drained ofi through the draintubesgl6. In the event impurities in the water restrict the overflow ofwater through the drain tubes the ball valves in the top of the casingand at the top of the first tube leg 48 are lifted by the water and sealwith their respective seats to prevent water being discharged into thearea around the device through the vent or upwardly open end of thefirsttube leg 48. The close spacing A supply means includes:

between the outer wallof the heater housing 22 and inner wall surface ofthe casing 20 limits the volume of water contained therebetween andrelatively quickly evaporates the water 78. As this occurs the heatertemperature again rises and opens the contacts of the thermal switch torefill the casing 20.

Referring also to FIG. 4, the current source wires and 64 may beconnected with the terminals of a forced draft furnace motor 80, or thelike, so that this humidifier may be operated only when the forced draftfurnace is in operation and supplyin heated air to the building.

bviously the invention IS susceptible to changes or alterations withoutdefeating its practicability, therefore, I do not wish to be confined tothe preferred embodiment shown in th drawings and described herein.

I claim: 1. A humidifier, comprising: a vertically disposed casingforming a primary water holding chamber, said casing having an openingadjacent its upper limit to permit steam to issue from the water holdingchamber; heater means within the depending end portion of said casing;

water supply 'means connected with the upper end portion of said casing;

tube means connected with the depending end portion of said casing andforming a secondary water holding chamber limiting the quantity of watercontained by said casing;

thermal switch means connected with the wall of the depending endportion of said casing and operatively connected with said water supplymeans for refilling said casing at predetermined intervals; and,

themial conduction means interposed between said switch means and saidcasing wall for increasing the thermal inertia of said switch means.

2. The humidifier according to claim 1 in which said heater meanscomprises: 7

a downwardly open housing coaxially received in close spaced relationwithin the depending end portion of said casing; and,

an electrical resistance heating element within said housing.

I 3. The humidifier according to claim'2 in which said water a watersupply pipe; a solenoid valve interposed in said water supply pipe; and,wiring connecting a source of electrical energy with said heatingelement, 1 said solenoid valve and said thermal switch means.

4. The humidifier according to claim 3 in which said tube meanscomprises:

a first tube substantially defining a U-shape and having an upwardlyopen leg portion extending upwardly substantially coextensive with saidcasing; and,

a second tube horizontally connected, at one end, with said first tubeabove the upper limit of said housing,

the other end of said second tube projecting downwardly. 5. Thehumidifier according to claim 4and further including:

normally open float valve and cage means coaxially connected withtheupper end portion of said casing and said first tube leg portion,respectively.

1. A humidifier, comprising: a vertically disposed casing forming aprimary water holding chamber, said casing having an opening adjacentits upper limit to permit steam to issue from the water holding chamber;heater means within the depending end portion of said casing; watersupply means connected with the upper end portion of said casing; tubemeans connected with the depending end portion of said casing andforming a secondary water holding chamber limiting the quantity of watercontained by said casing; thermal switch means connected with the wallof the depending end portion of said casing and operatively connectedwith said water supply means for refilling said casing at predeterminedintervals; and, thermal conduction means interposed between said switchmeans and said casing wall for increasing the thermal inertia of saidswitch means.
 2. The humidifier according to claim 1 in which saidheater means comprises: a downwardly open housing coaxially received inclose spaced relation within the depending end portion of said casing;and, an electrical resistance heating element within said housing. 3.The humidifier according to claim 2 in which said water supply meansincludes: a water supply pipe; a solenoid valve interposed in said watersupply pipe; and, wiring connecting a source of electrical energy withsaid heating element, said solenoid valve and said thermal switch means.4. The humidifier according to claim 3 in which said tube meanscomprises: a first tube substantially defining a U-shape and having anupwardly open leg portion extending upwardly substantially coextensivewith said casing; and, a second tube horizontally connected, at one end,with said first tube above the upper limit of said housing, the otherend of said second tube projecting downwardly.
 5. The humidifieraccording to claim 4 and further including: normally open float valveand cage means coaxially connected with the upper end portion of saidcasing and said first tube leg portion, respectively.